Thanks. I agree it would be nice if it compared the original input in the spirit of the purpose of the MD5 check. But documentation somewhere would be helpful.

I've actually been running it manually for a while, because it has never been quite as reliable as I was hoping. For some reason in April it missed a lot of data. I didn't have time to diagnose it and rebuild the table.

I don't really have the time to keep up with the increasing maintenance on this tool anymore. My plan is to put up some notices to see if anyone else is willing to take it over, and if not (which seems likely), I'll delete the rest.

Better link: https://phabricator.wikimedia.org/P252

Based on my search of enwiki, it only affected the API (only bots and a couple users using scripts were affected): http://hastebin.com/raw/iparusevuc
But not every API edit was affected, apparently - there almost 1000 other edits by bots to non-mainspace pages during the period that apparently worked fine.

I don't really have any intention to maintain that extension anymore. I don't know that it even works at all anymore.